Gavin Douglas had finally attained to the bishopric of Dunkeld in 1516, although only after a bitter struggle.

Douglas after July 1516 appears to have been in possession of his see, and to have patched up a diplomatic peace with the Duke of Albany, with whom he had proceed on May 17, 1517, to France to conduct the negotiations that ended in the Treaty of Rouen.

He was back in Scotland towards the end of June.

Albany's longer absence in France had permitted the party faction of the nobles to come to a head in a plot by James Hamilton, 1st Earl of Arran, to seize the Earl of Angus, the Queen's husband.

The issue of this plot is the well-known street fight known as Cleanse the Causeway, in which Gavin Douglas's part stands out in picturesque relief.

The skirmish is the result of enmity between the House of Hamilton and the "Red" Angus line of the House of Clan Douglas, both powerful noble families jealous of each other's influence over King James V.

The Hamiltons, led by Sir Patrick Hamilton of Kincavil, half-brother of the Earl of Arran, and Sir James Hamilton of Finnart, the earl's bastard son, attempt to apprehend the Earl of Angus.

The Earl of Arran in 1517 had become Lord Provost of Edinburgh.

In a dispute over the sale of a cargo of timber from a Dutch ship, he had sided with Leith merchants over the Edinburgh burgesses.

The Leithers, supported by Robert Barton, had ignored any of the rights of the burgesses, but Arran had still given them his support, enraging the Edinburgh traders.

The burgesses of Edinburgh during the skirmish see the opportunity for revenge, and take the side of Angus.

The fight goes badly for the Hamiltons, and Sir Patrick Hamilton and about seventy others are killed in the incident.

The Earl of Arran and Sir James fight their way out, and escape along a narrow close.

Stealing a nearby pack horse, they flee through the shallows of the Nor Loch marshes.